1. Field of the Invention
The invention relates to a cutting tool for machining by chip removal, having a supply of a cold-gas flow for cooling the immediate machine-cutting region.
In the case of machine-cutting of metallic materials in particular, a substantial amount of heat is produced in the immediate machine-cutting region, which can result in premature wear or failure of the machine-cutting tool. In order to keep this temperature production within limits and, at the same time, to improve the discharge of the chips from the machine-cutting region, it is usual for the immediate machine-cutting region of the cutting tool to be cooled by supplying a coolant. The coolant in this case may be gaseous or liquid, and routed by an internal supply via the cutting tool or by a supply via external arrangements to the immediate machine-cutting region.
A cutting tool with an internal supply for a liquid coolant is described, for example, in international patent disclosure WO 02/068142, corresponding to U.S. Pat. No. 6,705,805 B2.
Described in published, non-prosecuted German patent application DE 196 40 599 A1 is a cutting tool having an internal coolant supply, wherein cooled air is used for cooling the immediate machine-cutting region. A disadvantage in the case of this cutting tool is that the cold air must be produced, not within the tool, but outside the cutting tool and external equipment must be provided, in turn, for this purpose.
The production of cold gases in a low-temperature generator operating according to the Joule-Thompson effect through the supply of compressed gas, preferably compressed air, has likewise been known for a long time. The principle of such low-temperature generators is based on the operation of a vortex tube. In this case, compressed air is supplied to the vortex tube via a gas vorticizer in a vortex chamber, at normal temperature and at a few bars of pressure, and divided into a cold-air flow and a hot-air flow. The compressed air supplied to the vortex tube via the gas vorticizer is moved, circulating at high speed, along the inner wall of the vortex tube in the direction of a hot-gas nozzle at one end of the vortex tube. A portion of the air escapes, as a hot-air flow, through the hot-gas nozzle. The air that has not escaped is forcibly routed back, through the center of this air flow passing at high speed at the edge of the tube, in the opposite direction and at a substantially slower speed to the other end of the vortex wheel. This inner, slower air flow gives off heat to the outer, faster air flow and, up to the outlet at a cold-gas nozzle, cools to temperatures of down to 40° C.
Such low-temperature generators are described, for example, in U.S. Pat. Nos. 3,173,273 and 3,208,229, and are used in multiple instances as an external arrangement for the external supply of cold air into the immediate machine-cutting region of cutting tools.
It is disadvantageous in such cases that such external arrangements have to be individually aligned to each machine-cutting tool and fixed in place in such a way that the targeted supply of the cooling air flow into the immediate machine-cutting region remains assured, even in the case of an advance motion of the machine-cutting tool. This, however, can only be achieved with a substantial resource input.